Inpatient care and ambulatory care constitute the national and regional health care system. The relationship between the two subsystems is a significant topic that needs to be studied. Using publicly released data of China and international agencies, this paper preliminarily analyses the status and trends of hospital inpatient service provision and utilization and potential influencing factors, as well as the relationship between primary care and inpatient care. The results show that hospital admission rates in China are positively correlated with the degree of population aging and the availability of hospital beds, with synchronous growth observed in bed availability, utilization rates, and general practitioner resources. Hospital admission rates vary significantly across provinces. The hospitalization rate cannot be satisfactorily explained with commonly used indicators such as socioeconomic, population structure, and health resource allocation, but geographic density of hospital beds is related to socioeconomic and population indicators and other resource structures. Internationally, the supply of hospital beds is decreasing in high-income countries, increasing in middle-income countries, and remaining at a low level in low-income countries; the hospitalization rate is related to population aging, economic development, and hospital governance policies. It has been widely realized that excessive provision of expensive inpatient care will make the health system unsustainable. The healthcare system reforms are focusing on early disease prevention, consolidating and strengthening primary health care and basic medical care, and changing the traditional role of hospitals. High-income countries have reduced the supply and utilization of hospitalization services through various measures, middle-income countries are exploring the governance of hospitalization services, and low-income countries are exploring how to increase supply and utilization of inpatient care. Strengthening basic medical services does not necessarily lead to a reduction in inpatient services, but to improve the cost-effectiveness and fairness of regional medical services and optimize the use of inpatient resources. Effective governance of inpatient care and primary care, establishment and development of large-scale and competent basic medical services, implementation of shared care across the subsystems and apply gatekeeper systems, and measures to reduce avoidable hospitalizations for specific diseases and specific populations can help primary care contribute more rational inpatient care.